Pre-press color-proofing is a procedure that is used mainly by the printing industry for creating representative images of printed material without the high cost and time that is required to actually produce printing plates and set up a high-speed, high volume, printing press to produce an example of an intended image. An image may require several corrections and be reproduced several times to satisfy or meet customers requirements resulting in a large loss of profits and ultimately, higher costs to the customer.
One such commercially available image processing apparatus is arranged to form an intended image on a sheet of print media. Dye is transferred, from a sheet of dye donor material to the print media by applying a sufficient amount of thermal energy to the dye donor sheet material to form the intended image. This image processing apparatus generally includes a material supply assembly or carousel, and a lathe bed scanning subsystem or write engine, which includes a lathe bed scanning frame, translation drive, translation stage member, printhead, load roller, imaging drum, print media exit transport, and dye donor sheet material exit transport.
Operation of the image processing apparatus includes metering a length of the print media (in roll form) from the material assembly or carousel. The print media is then cut into sheet form of the required length and transported to the imaging drum. It is then wrapped around and secured onto the imaging drum. A load roller, which is also known as a squeegee roller, removes entrained air between the imaging drum and the print media or the print media dye donor material. Next, a length of dye donor material (in roll form) is metered out of the material supply assembly or carousel, and cut into sheet form of the required length. It is then transported to the imaging drum and wrapped around the periphery of the imaging drum. The load roller removes any air entrained between the imaging drum, print media, and the dye donor material. The dye donor material is superposed in the desired registration with respect to the print media, which has already been secured to the imaging drum.
After the dye donor sheet material is secured to the periphery of the imaging drum, the scanning subsystem or write engine, provides the scanning function. This is accomplished by retaining the print media and the dye donor sheet material on the imaging drum while it is rotated past the printhead to form an intended image on the print media. The translation drive then traverses both the printhead and translation stage member axially along the axis of the imaging drum in coordinated motion with the rotating imaging drum. These movements combine to produce the intended image on the print media.
After the intended image has been formed on the print media, the dye donor sheet material is removed from the imaging drum without disturbing the print media beneath it. The dye donor sheet material is then transported out of the image processing apparatus to a waste bin. Additional dye donor sheet materials are sequentially superimposed with the print media on the imaging drum, further producing an intended image. The completed intended image on the print media is then unloaded from the imaging drum and transported to an external holding tray on the image processing apparatus.
Various patents are considered relevant to this invention including commonly owned U.S. Pat. Nos. 5,777,658 and 5,755,520, which is hereby incorporated by reference.
Although the presently known and utilized image processing apparatus is satisfactory, a need exists to improve the capability of the imaging drum to hold print media at high rotational speeds thus improving throughput of utilized image processing apparatus.